惰化设计方法及其在煤粉干燥工艺中的应用

介绍了可燃粉尘极限氧含量的测试方法和测试设备,并给出了几种常见可燃粉尘的极限氧含量.根据气体均匀混合假设,导出了采用加压或抽真空惰化情况下惰化次数的计算方法和采用通流惰化情况下惰化时间的计算公式.提出了估算惰化流量的经验公式.给出了一个煤粉干燥工艺惰化设计的实例.正常运行时,惰化气体流量可通过循环风量和漏风率估算.在短时间停产时,应采用较小的惰化流量(每小时1~2个设备容积)维持惰化气氛.

Inerting Design and Its Application in Pulverized Coal Drying Process

Reasonable inerting design can guarantee the safety of a process to treat combustible materials and save running cost.The measurement and test apparatus of limiting oxygen concentration(LOC) of combustible dusts were introduced with the LOC of some conventional combustible dusts given.Assuming that the gas is mixed homogeneously,the calculation methods of inerting times using pressure-swing inerting and vacuum-swing inerting,and the inerting time using flow-through inerting were deduced.An empirical formula was given for determining the minimum inert gas flow rate.An example of inerting design was given for a pulverized coal drying process,where the inert gas flow rate can be estimated by recycled air flow rate and air leaking rate.When shut down for a short time,a lower inert gas flow rate(1 or 2 equipment volumes per hour) can be used to maintain inert atmosphere.